Age Calculator
Enter your date of birth to see your exact age in years, months and days, your age on any other date, and how long until your next birthday.
A Sunday.
Today in UTC. Change it for any past or future date.
Age today
years
and counting, to Friday 7 August 2026
Born 25 February 1996. Next birthday Thursday 25 February 2027, 202 days away, turning 31.
Your age in other systems
| System | Age | Rule |
|---|---|---|
| International | 30 | Zero at birth, plus one on each birthday. |
| Korean counting age, 세는 나이 | 31 | One at birth, plus one every 1 January. |
| Korean year age, 연 나이 | 30 | The current year minus the birth year. Ignores the birthday. |
Next milestone: One billion seconds old on Thursday 4 November 2027, 454 days away.
Counted in UTC (GMT), not counting today.
Change either and every figure above updates. Most date tools pick a zone and a counting rule silently, which is why two sites can answer the same question with different numbers.
How age is actually calculated
Age is not a division. You cannot get it by dividing days by 365.25 and rounding, and tools that do produce answers that are wrong by a day around birthdays.
The correct method counts calendar units in order. Take the years first: subtract the birth year from the current year, then take one back if the birthday has not happened yet this year. Then the months between the last birthday and today. Then the days.
That order matters because months are not the same length. From 31 January to 28 February is one month and no days in a common year. From 31 January to 1 March is one month and one day. This tool uses one rule throughout: a month is complete when the same day number arrives, or when the month runs out, whichever comes first. Because the count is built by walking forwards rather than by subtracting fields, the answer always adds back up: the years, months and days it reports, applied in that order to the birth date, land exactly on the date you asked about.
This is also why "months old" and "years old" do not convert cleanly. A child is 18 months old at a different moment from the one at which they are one and a half.
Born on 29 February
If you were born on a leap day you have a birthday in law every year, but the date only exists every fourth year.
There is no single rule. In England and Wales, for the purposes of reaching a particular age, a leapling born on 29 February is treated as having their birthday on 1 March in a common year. Elsewhere the convention is 28 February. Which one applies to you depends on where you are and what the age is for.
This tool defaults to 1 March and lets you switch to 28 February. In leap years it uses the real date. The difference only ever amounts to one day, but it is a day that decides whether someone turned 18 before or after a particular event, so we show which one we used rather than picking silently.
Korean age, and what changed in 2023
South Korea has used three different age systems at the same time, and until recently the same person could hold three different ages depending on which form they were filling in.
International age is the one most of the world uses. You are zero at birth and gain a year on each birthday.
Korean counting age, 세는 나이, starts at one on the day you are born and gains a year on 1 January, not on your birthday. So a baby born on 31 December is two years old the next day.
Year age, 연 나이, is simply the current year minus your birth year. It ignores the birthday entirely and is used for things that need to apply to a whole cohort at once, such as school entry and military conscription.
On 28 June 2023 the International Age Unification Act took effect and standardised legal and administrative age on the international system. Counting age is still used constantly in everyday conversation, which is why people still need to convert between them.
The panel in the result shows all three at once.
Age at a date that is not today
The second date field is editable, and it is the part of this tool most people miss.
Set it to a date in the past to find out how old you were when something happened. Set it to a date in the future to find out how old you will be. Set it to somebody else's date of birth to get the exact age difference between two people.
This is the version of the question that actually gets asked. "How old was I in September 2001", "how old will I be when the mortgage ends", "exactly how much older is my sister". A calculator that only knows about today answers none of them.
Frequently asked questions
How do I calculate my exact age?
Enter your date of birth. The tool counts complete years first, then complete months, then the remaining days, which is how age is normally reckoned. It does not divide days by 365.
When is my next birthday?
The result shows the date, the weekday and how many days away it is, counted from the date in the "age at" field.
What if I was born on 29 February?
Your birthday exists as a date only in leap years. For age purposes England and Wales treat it as 1 March in a common year, and some other places use 28 February. This tool defaults to 1 March, tells you which it used, and lets you switch.
What is my Korean age?
The panel in the result shows all three systems at once. Since 28 June 2023, South Korean law and administration use the international age. Counting age, still common in conversation, is one higher at birth and increments every 1 January.
Can I work out my age on a past or future date?
Yes. Change the "age at" field. You can also put in another person’s date of birth to get the exact difference between two ages.